About the speaker sound system：
The main technical indicators of the sound system are: frequency characteristics, signal-to-noise ratio, dynamic range, transient response, stereo separation, and stereo balance.
Frequency characteristics: The frequency range (frequency response) when the audio equipment is played back and the relationship between signal amplitude and frequency (magnitude and frequency characteristics). The unit of the amplitude is dB, and the unit of the frequency is Hz. The frequency response of the audio system is at least 32-18000 Hz, and the signal amplitude variation within this frequency range should be less than 2 dB.
Signal-to-noise ratio: The logarithm of the ratio of wanted signal to noise at the same reference point. In the speaker input point, the signal-to-noise ratio is 70dB, and the human earphone noise is almost inaudible to one meter, and the Hi-Fi system generally reaches 100dB or more.
Dynamic range: The logarithm of the ratio of the maximum undistorted output power to the system noise output power at rest during playback of the audio equipment. Hi-Fi systems generally reach more than 100dB.
Distortion: The degree of distortion of the source signal when the audio device is playing back. There are harmonic distortion, crosstalk, and transient distortion. Hi-Fi system harmonic distortion is generally less than 1%.
Stereo resolution: The degree of separation of the left and right channels. Reflects the degree of crosstalk between the left and right channels.
Stereo Balance: The difference between the signal gains of the left and right channels.
Mario TECH Bluetooth Speaker sound system：
Builtin functions:Bluetooth, Bluetooth Handsfree, TF card, USB
Case:ABS+Silicon Rubber / Metal
Power supply:Battery/Micro input
Support:MP3 / WMA / WAV
BT Working range:≥10M
TF card:Support 32GB
Input power:5V 0.3A
Battery:Built-in rechargeable 600mA Lithium Battery